Methyl paraben as a sex pheromone in canine urine – is the question still open?

Abstract

The literature concerning the issue of canine sex pheromones includes reports presenting completely conflicting opinions about the chemical composition of the canine urine in the context of semiochemical communication. At present, the predominant report cited by many different authors is the article published in Science in 1979 by Goodwin at al., presenting methyl p-hydroxybenzoate (methyl paraben) as the main canine sex pheromone. While it has been proved that pure methyl paraben lacks semiochemical activity as do commercially available products containing this substance (Eau D'Estrus, Synbiotics, USA), in view of the conflicting published reports the aim of this study was to revaluate using modern techniques the presence of methyl p-hydroxybenzoate in canine urine during different phases of the ovarian cycle. Ten female dogs of different breeds were used. Urine samples from bitches collected during various stages of the ovarian cycle were examined with using the SPME and GC/MS methods. Methyl paraben was not detected in any of the samples. In conclusion, because of the lack of methyl-p-hydroxybenzoate in the samples examined, the present study confirmed negative opinions on the possibility of this substance playing a crucial role in semiochemical communication during reproduction in dogs (Canis familiaris).

Parabens and Their Metabolites in Pet Food and Urine from New York State, United States

“…EtP and PrP were found in dog urine at mean concentrations of 1.0 and 0.5 ng/mL, respectively, which were 2 orders of magnitude lower than MeP concentrations. MeP has been reported as a sex pheromone in canines, and some commercially available male sexual stimulants in the United States (as recommended by veterinarians and dog breeders) contain MeP. , The mean concentration of total parent parabens in dog urine was 130 ng/mL, which was 2- to 11-fold higher than those reported for human urine from the U.S. population. , Among the metabolites, 4-HB was found highest, at a mean concentration of 5150 ng/mL, which was 7 to 8 times higher than those reported for human urine from the U.S. population . It is noteworthy that 4-HB has been used as a food preservative and corrosion inhibitor and as an additive in drugs, cosmetics, and dyes.…”

“…Parabens are esters of p -hydroxy benzoic acid and are broad-spectrum antimicrobial agents used in personal care products, pharmaceuticals, and food products. − Both in vitro and in vivo studies have demonstrated that parabens are endocrine-disrupting chemicals (Darbre and Harvey, 2008) . Exposure to parabens was linked to reproductive effects in men. , The U.S. FDA and the European Food Safety Authority (EFSA) have set the permissible limits for parabens in human food products. , Exposure of humans to parabens, however, is ubiquitous. − Nevertheless, little is known on the exposure of pet animals to parabens and their derivatives . We determined the concentrations of parabens and their metabolites in cat and dog urine as well as pet food available commercially for these companion animals.…”

“…39−41 Nevertheless, little is known on the exposure of pet animals to parabens and their derivatives. 42 We determined the concentrations of parabens and their metabolites in cat and dog urine as well as pet food available commercially for these companion animals.…”

The Case of Atypical Sexual Attractiveness in a Male Domestic Dog—A Case Study

“…This could not be the explanation for the case described here, firstly because no products containing these compounds had been used on the case dog, and because other studies have excluded the pheromonal effect of methylparaben in dogs [ 18 , 59 , 60 ]. Finally, despite the hypothesis of Goodwinn et al [ 8 ], the presence of this compound has been excluded from the group of compounds present in the urine of the bitch in estrus [ 15 , 61 ].…”

The Role of Urine in Semiochemical Communication between Females and Males of Domestic Dog (Canis familiaris) during Estrus

“…In domestic dogs, mechanisms of attracting males by a female in estrus were studied and attempts to identify the substance(s) responsible for this phenomenon were undertaken [ 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 ]. In most research, urine was considered a main source of attractants, although effective artificial sex pheromones have not yet been definitively identified [ 20 ].…”